nches, perhaps, in aperture--will serve to supply profitable amusement
to those who know how to apply its powers. I have often seen with
pleasure the surprise with which the performance even of an opera-glass,
well steadied, and directed towards certain parts of the heavens, has
been witnessed by those who have supposed that nothing but an expensive
and colossal telescope could afford any views of interest. But a
well-constructed achromatic of two or three inches in aperture will not
merely supply amusement and instruction,--it may be made to do useful
work.

The student of astronomy is often deterred from telescopic observation
by the thought that in a field wherein so many have laboured, with
abilities and means perhaps far surpassing those he may possess, he is
little likely to reap results of any utility. He argues that, since the
planets, stars, and nebulae have been scanned by Herschel and Rosse, with
their gigantic mirrors, and at Pulkova and Greenwich with refractors
whose construction has taxed to the utmost the ingenuity of the
optician and mechanic, it must be utterly useless for an unpractised
observer to direct a telescope of moderate power to the examination of
these objects.

Now, passing over the consideration that a small telescope may afford
its possessor much pleasure of an intellectual and elevated character,
even if he is never able by its means to effect original discoveries,
two arguments may be urged in favour of independent telescopic
observation. In the first place, the student who wishes to appreciate
the facts and theories of astronomy should familiarize himself with the
nature of that instrument to which astronomers have been most largely
indebted. In the second place, some of the most important discoveries in
astronomy have been effected by means of telescopes of moderate power
used skilfully and systematically. One instance may suffice to show what
can be done in this way. The well-known telescopist Goldschmidt (who
commenced astronomical observation at the age of forty-eight, in 1850)
added fourteen asteroids to the solar system, not to speak of important
discoveries of nebulae and variable stars, by means of a telescope only
five feet in focal length, mounted on a movable tripod stand.

The feeling experienced by those who look through a telescope for the
first time,--especially if it is directed upon a planet or nebula--is
commonly one of disappointment. They have been told that such